There are many different strategies to this but I would just reccomend to build your stations using a different command block then that of your others ships, just like how the terrans have a small command block for their ships and a larger, tougher one for their stations.
Another way could be to make the ship p larger than 8k (sure people could still get over that using mods but not everyone runs infinite P) so they can't use it because it is over max p. I reccomend not making every station huge in this way but rather offer the station command block to supply most of the p so every station you build doesn't have to be huge. There are ways to thwart both of these strategies but they should be good enough.